Lamp



C. ADLER. JR

June 15, 1937.

LAMP

Filed Oct. 17, 1936 45 evacuated type.

Patented June 15, 1937 PATENT OFFICE LAMP Charles Adler, Jr., Baltimore, Md.

Application October 17, 1936, Serial No. 106,248

3 Claims.

This invention relates to lamps of the incandescent type useful for numerous purposes, but particularly applicable to signal and exit systems.

An object of the invention is to provide a lamp having a plurality of filaments disposed in spaced relation and one of the filaments of longer life and lower wattage than the other.

Another object of the invention is to provide a lamp wherein the distance of spacing of the filaments is so controlled that when one filament burns out, the other filament will not be destroyed due to arcing. This spacing is important, for example, in hospital signalling, for the reason that when the lamp is normally illuminated, i. e.,

both filaments are incandescent, it is possible, be-

cause of their spacing, for a nurse to conveniently observe that the lamp is normally illuminated; and when one filament burns out, it can also be readily observed that there is only one source 90 of light in the lamp instead of two, and thus report this fact, and have the lamp replaced.

A further object of the invention is to provide a lamp wherein the filaments are permanently and completely electrically connected in parallel within the lamp.

Still another object of the invention is to provide a lamp having a portion or the entire area of the bulb formed with a diffusing means such as frosting or the entire area may be colored for the same purpose. Where the entire area is frosted or colored and the main filament of high wattage burns out, the remaining incandescent low wattage filament will produce a spot indicating the failure as well as serve as an illuminating 35 means.

Referring to the drawing:

Figure 1 is a top view partly in section of a lamp in accordance with the present invention,

Figure 2 is a view showing a portion of the bulb 40 at the top of the lamp frosted, and

Figure 3 is a view showing the entire area of the bulb frosted or colored.

Referring to the drawing, the numeral III indicates an incandescent lamp of the gas filled or This lamp, comprises a clear glass bulb II and the usual screw threaded base [2 into which the bulb is sealed. The usual stem [3 and pillar 13 are provided within the lamp, and supported by the said pillar are the filaments 50 I4 and 15. These filaments are shown as circular,

but similar elongated filaments of other types may be used. The filaments as shown are disposed in longitudinal alignment and the distance of their spacing is such that should one filament 55 burn out, no arcing will occur such as would destroy the remaining filament. This spacing, as previously explained, is advantageous, in that for hospital signalling purposes, for example, a nurse may determine that the lamp is properly functioning by readily observing that both filaments of the lamp are incandescent. That is to say, this condition, or the fact that one of the filaments has failed, is easily determinable at a distance without the necessity of calling an electrician or making a close scrutiny of the lamp. The filaments are electrically and completely connected in parallel, by means of the lead wires I6 and II, as shown at l8 which terminate in the insulated bottom of the base and at the screw threaded ferrule surrounding the same respectively as shown at l9 and 20, for connection in the usual lamp socket.

The lamp has a major filament I 4 the life of which is for purposes of illustration about 1500 hours and the wattage between substantially 25 and 50 watts; the auxiliary filament l5 has a considerably longer life e. g. 3000 hours and a wattage of about 7 to 10 watts. The secondary filament as shown is disposed close to the tip of the bulb.

As will be observed, if the major filament burns out, the auxiliary filament will remain illuminated.

In Figure 2 I have shown the lamp as provided with a light diffusing means, here in the form of a frosted or translucent tip area 2|, whereby when the major filament is extinguished, the auxiliary filament maintains the frosted area illuminated.

In Figure 3, I have shown the bulb provided with a. diffusing means, e. g. the entire area of the bulb is frosted or colored or otherwise rendered translucent, whereby when the lamp is used for an "exit or night light, and the safeguarding of life and. property depends on its continuous illumination, if the major filament be extinguished, there will still remain an illuminated area created by the auxiliary filament in co-operation with the frosted or colored area adjacent the tip of the bulb, and an indication of the failure, is thus displayed by contrast with the darker major portion of the bulb.

I claim:

1. An indicator lamp for signal purposes comprising a bulb and a base, means for supporting filaments within the bulb, and major and auxiliary filaments electrically connected in parallel and supported in unscreened substantially longitudinal alignment, said auxiliary filament having a substantially longer life than the major filament and disposed substantially more remote from the base of the lamp, the spacing of said filaments from each other being such that the filaments are independently discernible when both are incandescent.

2. An indicator lamp for signal purposes comprising a bulb and base, means for supporting filaments within the bulb, and major and auxiliary filaments electrically connected in parallel and supported in unscreened substantially longitudinal alignment, said auxiliary filament having a substantially longer lii'e than the major filament and disposed substantially more remote from the base of the lamp, the spacing of said filaments from each other being such that the filaments are independently discernible when both are incandescent, a portion of the bulb adjacent said auxiliary filament being provided with light difiusing means.

3. An indicator lamp for signal comprising a bulb provided with a light dii'iusing means over substantially its entire area. and a base. means for supporting filaments within the bulb, and major and auxiliary filaments electrically connected in parallel and supported in unscreened substantially longitudinal alignment, said auxiliary filament having a substantially longer life than the major filament and disposed substantially more remote from the base oi the lamp, the spacing of said filaments from each other being such that their presence is independently distinguishable when both are incandescent.

CHARLES ADLER, JR. 

